Unmarried heterosexual cohabitation has risen sharply in recent years in the United States. Today, the majority of marriages and remarriages begin as cohabiting relationships, most younger men and women have cohabited or will cohabit, and two-fifths of children born in the early 1990s will spend time in a cohabiting-parent family. Incorporating cohabitation into demographic studies has become crucial for evaluating union formation and dissolution, fertility, the life-course of individuals, children's well being, and the likely direction of future changes in family patterns. [unreadable] [unreadable] This project undertakes exploratory research on the meanings of cohabiting unions in the United States. Framed by symbolic interactionist and exchange theories, our project focuses on the following three issues: (1) how and why cohabiting unions begin; (2) partner and parenting roles in cohabiting unions; and (3) how and why cohabiting unions end. We collect and analyze qualitative data from focus groups and in-depth interviews with young Hispanic, African American, and white men and women, and with both partners in dating, cohabiting, and married couples, to address these questions. The importance of qualitative research on cohabitation has been recognized by the Demographic and Behavioral Sciences Branch of the National Institute for Child Health and Human Development, by the Federal Interagency Forum on Child and Family Statistics, and by members of the family demography research community. The project is part of the research team's continuing endeavor to understand the implications of unmarried cohabitation, marriage, divorce, and childbearing in the contemporary United States among diverse populations. [unreadable] [unreadable]